Health check of a site migration around its go-live date: the Migration Compare analysis of the GSC Wizard app (without brand terms, the search-type split or the country / device filters of a saved migration; notes says what differs). Returns recovery (side B clicks per day as a % of side A clicks per day before go-live), pace against the recovery a migration on track reaches by now, momentum, a projected recovery with milestone dates, URL success per migration unit, a 0-100 risk score with its factors, prioritised recommendations, redirect status counts from the stored redirect checks, the top lost pages, redirect problems, lost queries and losing sections, the old-to-new impression handover, the click change split into demand / position / CTR effects, the country and device splits (segments) with their recommendations, and a launch checklist. siteUrl is the OLD property (side A); pass siteUrlB (the new property) for a domain move and omit it when the migration happened inside one property. Pass goLiveDate, or a migrationId from list_migrations to reuse a migration saved in the app (its properties, URL prefixes or regexes, go-live date, windows, mapping label and Only mapped URLs setting; explicit arguments override it). Redirect mappings are the ones saved for the property pair (add_migration_redirects or the app); without any, pages are joined by path. onlyMapped is the app's "Only mapped URLs": with saved mappings, the totals, recovery and health count only the pages the mappings claim, and so do the country and device splits of a side read from the warehouse (segments.scope says which; each 10 warehouse queries of those splits cost one more rate-limit unit). Windows as in compare_migration: windowStrategy "recent" (default), "from-go-live" or "full", windowDays (default 28), yoyBaseline. Page and query reads cover at most the top 25,000 rows by clicks per side and window, and at most 10,000 redirect mappings are analysed (each 2,000 costs one more rate-limit unit); truncated says when a cap was reached. health is null until a post-launch day has final data.